CVE-2026-21533

Microsoft Windows Improper Privilege Management

7.8 HIGHActively exploited (CISA KEV)EPSS 4.13%

Published10 Feb 2026
Added to CISA KEV10 Feb 2026
Remediation due3 Mar 2026

Description

Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally.

CVSS 3.1 breakdown

Attack vectorLocal

Attack complexityLow

Privileges requiredLow

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft Windows 10 1607< 10.0.14393.8868

Microsoft Windows 10 1809< 10.0.17763.8389

Microsoft Windows 10 21h2< 10.0.19044.6937

Microsoft Windows 10 22h2< 10.0.19045.6937

Microsoft Windows 11 23h2< 10.0.22631.6649

Microsoft Windows 11 24h2< 10.0.26100.7781

Microsoft Windows 11 25h2< 10.0.26200.7781

Microsoft Windows Server 2012r2

Microsoft Windows Server 2016< 10.0.14393.8868

Microsoft Windows Server 2019< 10.0.17763.8389

Microsoft Windows Server 2022< 10.0.20348.4711

Microsoft Windows Server 2022 23h2< 10.0.25398.2149

Microsoft Windows Server 2025< 10.0.26100.32313

Remediation

Fixed in

Microsoft Windows 10 1607≥ 10.0.14393.8868

Microsoft Windows 10 1809≥ 10.0.17763.8389

Microsoft Windows 10 21h2≥ 10.0.19044.6937

Microsoft Windows 10 22h2≥ 10.0.19045.6937

Microsoft Windows 11 23h2≥ 10.0.22631.6649

Microsoft Windows 11 24h2≥ 10.0.26100.7781

Microsoft Windows 11 25h2≥ 10.0.26200.7781

Microsoft Windows Server 2016≥ 10.0.14393.8868

Microsoft Windows Server 2019≥ 10.0.17763.8389

Microsoft Windows Server 2022≥ 10.0.20348.4711

Patch & vendor advisories

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21533

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21533Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21533US Government Resource
https://www.vicarius.io/vsociety/posts/cve-2026-21533-detection-script-privilege-escalation-vulnerability-in-windows-remote-desktopThird Party Advisory
https://www.vicarius.io/vsociety/posts/cve-2026-21533-mitigation-script-privilege-escalation-vulnerability-in-windows-remote-desktopMitigationThird Party Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-21533 being actively exploited?

Yes. CVE-2026-21533 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 10 Feb 2026.

How severe is CVE-2026-21533?

CVE-2026-21533 has a CVSS 3.1 base score of 7.8, rated high. EPSS estimates a 4.13% probability of exploitation.

Which products are affected by CVE-2026-21533?

Affected products include Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 23h2, and 8 more.

How do I fix CVE-2026-21533?

Upgrade affected software to a fixed version, for example Microsoft Windows 10 1607 10.0.14393.8868, Microsoft Windows 10 1809 10.0.17763.8389, Microsoft Windows 10 21h2 10.0.19044.6937 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-21533 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

See how prioritisation works Book a demo

Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.